2,996 research outputs found
The role of the pre-supplementary motor area in the control of action
No full textAlthough regions within the medial frontal cortex are known to be active during voluntary movements their precise role remains unclear. Here we combine functional imaging localisation with psychophysics to demonstrate a strikingly selective contralesional impairment in the ability to inhibit ongoing movement plans in a patient with a rare lesion involving the right pre-supplementary motor area (pre-SMA), but sparing the supplementary motor area (SMA). We find no corresponding delay in simple reaction times, and show that the inhibitory deficit is sensitive to the presence of competition between responses. The findings demonstrate that the pre-SMA plays a critical role in exerting control over voluntary actions in situations of response conflict. We discuss these findings in the context of a unified framework of pre-SMA function, and explore the degree to which extant data on this region can be explained by this function alone
Interoception after frontal brain injury: A systematic review.
No full textpeer reviewed[en] OBJECTIVE: Interoception is crucial for emotional processing. It relies on the bidirectional connections between the insula, a crucial structure in interoception, and the frontal lobe, which is implicated in emotional experiences. Acquired frontal brain injury often leads to emotional disorders. Our goal was to explore the interoceptive profiles of patients with frontal lesions with or without insular involvement.
METHOD: Given the neuroanatomical links between interoception and emotions, we conducted a systematic Preferred Reporting Items for Systematic Reviews and Meta-analyses guided review of studies assessing at least one dimension of interoception in adults with acquired frontal injuries, with or without associated insular lesions.
RESULTS: Seven articles were included. The review indicated that interoceptive accuracy declines after frontal injuries. The two studies that investigated interoceptive sensitivity found lower scores in patient groups. Finally, inconsistent results were found for interoceptive metacognition after frontal damage.
CONCLUSIONS: This review is the first to explore interoceptive disorders after acquired frontal brain injury. The findings reveal deficits in cardiac interoceptive accuracy and interoceptive sensitivity following frontal damage. Inconsistent results were observed for interoceptive metacognition. Further research is needed to confirm the presence of interoceptive deficits following a frontal lesion. Additionally, the relationship between interoceptive deficits and emotional disorders, often reported after frontal brain injury, should be investigated
Alice Bishop Cornell
No full textDaguerreotype of Alice Bishop Cornell. She is photographed fully frontal in a white-collared dress with her hair up.https://digitalcommons.otterbein.edu/cornell_images/1013/thumbnail.jp
Neural basis for priming of pop-out during visual search revealed with fMRI
No full textMalikovic and Nakayama first showed that visual search efficiency can be influenced by priming effects. Even "pop-out" targets (defined by unique color) are judged quicker if they appear at the same location and/or in the same color as on the preceding trial, in an unpredictable sequence. Here, we studied the potential neural correlates of such priming in human visual search using functional magnetic resonance imaging (fMRI). We found that repeating either the location or the color of a singleton target led to repetition suppression of blood oxygen level-dependent (BOLD) activity in brain regions traditionally linked with attentional control, including bilateral intraparietal sulci. This indicates that the attention system of the human brain can be "primed," in apparent analogy to repetition-suppression effects on activity in other neural systems. For repetition of target color but not location, we also found repetition suppression in inferior temporal areas that may be associated with color processing, whereas repetition of target location led to greater reduction of activation in contralateral inferior parietal and frontal areas, relative to color repetition. The frontal eye fields were also implicated, notably when both target properties (color and location) were repeated together, which also led to further BOLD decreases in anterior fusiform cortex not seen when either property was repeated alone. These findings reveal the neural correlates for priming of pop-out search, including commonalities, differences, and interactions between location and color repetition. fMRI repetition-suppression effects may arise in components of the attention network because these settle into a stable 1. attractor state" more readily when the same target property is repeated than when a different attentional state is required
Modern Concepts of Frontal Sinus Surgery
No full textObjectives/Hypothesis: To validate the endonasal surgical approach to frontal sinus in inflammatory sinus disease, trauma, and selective tumor surgery, and to define the role of external approaches to the frontal sinus. Endonasal frontal sinusotomy can range from endoscopic removal of obstructing frontal recess cells or uncinate process to the more complex unilateral or bilateral removal of the frontal sinus floor as described in the Draf IT-m drainage procedures. In contrast, the osteoplastic frontal sinusotomy remains the "gold standard" for external approaches to frontal sinus disease. Methods: A retrospective review of 1286 patients undergoing either endonasal or external frontal sinusotomy by the authors at four university teaching programs from 1977. Prior author reports were updated and previously unreported patient series were combined. Results: Six hundred thirty-five patients underwent type I frontal sinusotomy, 312 type II sinusotomy, and 156 type III sinusotomy. A successful result was seen in these groups, 85.2% to 99.3%, 79% to 93.3%, and 91.5% to 95%, respectively. External frontal sinusotomy or osteoplastic frontal sinusotomy was successfully performed in 187 of 194 patients. Clinical symptoms, endoscopic findings, computed tomography, and magnetic resonance image scanning, and reoperation rate measured postoperative success. Conclusions: A stepwise approach to the surgical treatment of frontal sinusitis, trauma, and selective benign tumors yields successful results as defined by specific criteria which vary from 79% to 97.8%. The details of specific techniques are discussed, essential points emphasized, and author variations noted
Age-related Differences in Implicit Sequence Learning and Consolidation across the Human Life Span: Implications for the Functioning of the Fronto-Striatal Circuitry
No full textImplicit sequence learning occurs when information is acquired from an environment of complex stimuli without conscious access either to what was learned or to the fact that learning occurred. In everyday life, this learning mechanism is crucial for adapting to the environment and for predicting events unconsciously. Despite the growing interest in implicit learning in the past decades, there has been relatively little research on life-long development of implicit sequence learning and on offline processing of implicitly learned information (i.e., consolidation). Here, we present three studies investigating these issues. In Experiment I, we investigated implicit sequence learning from 4 to 85 years of age and found a marked decrease in learning performance - measured by raw reaction time (RT) – around age of 12. This decrement can be explained by a competition between two fundamentally different forms of learning (model-free and model-based) suggesting that after adolescence frontal lobe-mediated model-based learning has larger effect on the expression of implicit sequence knowledge, while before adolescence basal ganglia-dependent model-free learning is more influencing. As a growing body of data has shown that frontal lobe-mediated processes are disrupted in hypnosis, we tested this assumption in Experiment II by comparing implicit sequence learning in hypnosis and in waking alert state. We found that hypnosis boosted sequence learning in young adults. In addition, this boosting effect was mediated by frontal lobe related executive functions. Finally, we investigated consolidation of implicit sequence knowledge in young and elderly adults after 12-, 24-hour or a 1-week delay period in order to determine age-related differences not only in online learning, but also in offline processing of the learned material (Experiment III). We found that consolidation is not a single process, rather there are multiple mechanisms (e.g., sequence-specific, general skill learning) which are differentially affected by aging and the course of time. Our results contribute not only to the better understanding of learning on a behavioral level, but also to understanding the age-related changes in brain plasticity in healthy participants across the human life span. In addition, these findings can help better understand neurodevelopmental (e.g., autism, dyslexia), neurodegenerative (e.g., Parkinson’s Disease, Huntington’s Disease) and age-related disorders where related brain structures are affected. Finally, our findings can lead to the development of more effective diagnostic tools, training methods and rehabilitation programs
The Involvement of Occipital and Inferior Frontal Cortex in the Phonological Learning of Chinese Characters
No full textNeural changes related to the learning of the pronunciation of Chinese characters in English speakers were examined using fMRI. We examined the item-specific learning effects for trained characters and the generalization of phonetic knowledge to novel transfer characters that shared a phonetic radical (part of a character that gives a clue to the whole character's pronunciation) with trained characters. Behavioral results showed that shared phonetic information improved performance for transfer characters. Neuroimaging results for trained characters over learning found increased activation in the right lingual gyrus, and greater activation enhancement in the left inferior frontal gyrus (Brodmann's area 44) was correlated with higher accuracy improvement. Moreover, greater activation for transfer characters in these two regions at the late stage of training was correlated with better knowledge of the phonetic radical in a delayed recall test. The current study suggests that the right lingual gyrus and the left inferior frontal gyrus are crucial for the learning of Chinese characters and the generalization of that knowledge to novel characters. Left inferior frontal gyrus is likely involved in phonological segmentation, whereas right lingual gyrus may subserve processing visual-orthographic information
ALICE forward rapidity upgrades
No full textTwo forward rapidity upgrades of the ALICE apparatus at the LHC are presented: the Muon Forward
Tracker (MFT) and the Fast Interaction Trigger (FIT). Their designs are driven by physics
performance studies, which have been done using MC simulations. Several prototypes have been
tested. Currently the detector design phase has ended. The final layouts, geometries and expected
performance figures are presented. The latest developments from the test of the prototypes are
discussed.
The MFT will improve the performance of the ALICE Muon Spectrometer by adding vertexing
capabilities to the system. The elementary component of the MFT is a Monolithic Active Pixel
Sensor (MAPS), using the TowerJazz 0.18 µm technology called ALPIDE. ALPIDE has been developed
by the ALICE collaboration for upgrades of the Inner Tracking System and the MFT. The
MFT will consist of five detection planes forming a cone-like structure located between the interaction
point and the frontal absorber of the Muon Spectrometer. The quality of track matching
between the MFT and the Muon Spectrometer has been evaluated using Monte Carlo simulations.
The same simulations were also used to extract the pointing accuracy of reconstructed
muon tracks, which defines the resolution of the reconstructed vertex position.
FIT has both online and offline functionalities. It will send online luminosity feedback to the LHC
and it will generate minimum-bias and centrality-based triggers for ALICE. It is also expected
to provide the offline information on the precise collision time for the Time-Of-Flight detector,
as well as on forward multiplicity, centrality and event plane for Pb-Pb collisions. It will be
composed of two Cherenkov detector arrays, surrounding the beam pipe on both sides of the
interaction point, and one scintillator ring. The arrays will use Micro Channel Plate (MCP-PMT)
technology to detect Cherenkov light and sectors of the scintillator ring will be optically coupled
with Fine Mesh PMTs. The arrays provide good time response, while the scintillator ring allows
for larger active area coverage. The extensive simulations verify the performance of the detector
in terms of centrality and event-plane resolution. Additionally, the test results of the prototype of
a single Cherenkov detector module, installed in ALICE, are presented.peerReviewe
A Multivariate Surface-Based Analysis of the Putamen in Premature Newborns: Regional Differences within the Ventral Striatum
No full textMany children born preterm exhibit frontal executive dysfunction, behavioral problems including attentional deficit/hyperactivity disorder and attention related learning disabilities. Anomalies in regional specificity of cortico-striato-thalamo-cortical circuits may underlie deficits in these disorders. Nonspecific volumetric deficits of striatal structures have been documented in these subjects, but little is known about surface deformation in these structures. For the first time, here we found regional surface morphological differences in the preterm neonatal ventral striatum. We performed regional group comparisons of the surface anatomy of the striatum (putamen and globus pallidus) between 17 preterm and 19 term-born neonates at term-equivalent age. We reconstructed striatal surfaces from manually segmented brain magnetic resonance images and analyzed them using our in-house conformal mapping program. All surfaces were registered to a template with a new surface fluid registration method. Vertex-based statistical comparisons between the two groups were performed via four methods: univariate and multivariate tensor-based morphometry, the commonly used medial axis distance, and a combination of the last two statistics. We found statistically significant differences in regional morphology between the two groups that are consistent across statistics, but more extensive for multivariate measures. Differences were localized to the ventral aspect of the striatum. In particular, we found abnormalities in the preterm anterior/inferior putamen, which is interconnected with the medial orbital/prefrontal cortex and the midline thalamic nuclei including the medial dorsal nucleus and pulvinar. These findings support the hypothesis that the ventral striatum is vulnerable, within the cortico-stiato-thalamo-cortical neural circuitry, which may underlie the risk for long-term development of frontal executive dysfunction, attention deficit hyperactivity disorder and attention-related learning disabilities in preterm neonates. © 2013 Shi et al
Asymmetric Frontal Brain Activity and Parental Rejection
No full textAsymmetric frontal brain activity has been widely implicated in reactions to emotional stimuli and is thought to reflect individual differences in approach-withdrawal motivation. Here, we investigate whether asymmetric frontal activity, as a measure of approach-withdrawal motivation, also predicts charitable donations after a charity's (emotion-eliciting) promotional video showing a child in need is viewed, in a sample of 47 young adult women. In addition, we explore possibilities for mediation and moderation, by asymmetric frontal activity, of the effects of intranasally administered oxytocin and parental love withdrawal on charitable donations. Greater relative left frontal activity was related to larger donations. In addition, we found evidence of moderation: Low levels of parental love withdrawal predicted larger donations in the oxytocin condition for participants showing greater relative right frontal activity. We suggest that when approach motivation is high (reflected in greater relative left frontal activity), individuals are generally inclined to take action upon seeing someone in need and, thus, to donate money to actively help out. Only when approach motivation is low (reflected in less relative left/greater relative right activity) do empathic concerns affected by oxytocin and experiences of love withdrawal play an important part in deciding about donations. © The Author(s) 2012
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